The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 24, 2008
Filed:
Oct. 13, 2005
Ko Ishizuka, Saitama, JP;
Ko Ishizuka, Saitama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Position detection apparatus comprises: an incident unit that forms a parallel beam from a light beam of a light source and supplies the parallel beam to a beam splitter in a way that the separated beams, obtained from the parallel beam by the beam splitter, are respectively incident upon the reference surface and the measurement target surface at an angle; and a reflection unit that reflects the separated beams, which have been reflected by the reference surface and the measurement target surface and integrated to a light path by the beam splitter, to be supplied to the beam splitter as a parallel beam along the light path, and generates a signal corresponding to a phase difference of the separated beams by interfering a light beam that has been supplied from the reflection unit, separated by the beam splitter, reflected by the reference surface and the measurement target surface, and integrated again to a light path by the beam splitter.